Asian ethnic subgroups, particularly Chinese and Vietnamese, have higher rates of mastectomy for early stage breast cancer, raising concerns about possible over-treatment. To address the factors affecting treatment decision-making processes and consequent quality of life in these groups, the roles of socio-cultural, demographic, and clinical factors must first be determined for each ethnic group. For this 2-year developmental/pilot study, we propose to apply qualitative research methods to inform the development of linguistically and culturally appropriate questionnaires related to treatment decision-making and quality of life, and to pilot test the instruments in a population-based sample of non-Hispanic White, Chinese, and Vietnamese women recently diagnosed with breast cancer. Study results will form the basis for planning a larger, population-based epidemiologic study. Study aims are to: 1) identify the socio-cultural, co-decision making, provider communication, and other factors in treatment decision-making processes and quality of life in each ethnic group through the following procedures: a) focus group interviews with patients, b) qualitative interviews with patients, and c) qualitative interviews with patients' co-decision makers; 2) determine provider practices and perceptions regarding treatment recommendations and decision-making processes via provider surveys; and 3) develop and test ethnic-specific epidemiologic questionnaires through cognitive interviews and an epidemiologic pilot study in a population-based patient sample. An overall enrollment of 43 White, 56 Chinese, and 43 Vietnamese patients; 20 family or friends identified as the co-decision maker; and 60 providers are expected. As little is known about factors contributing to disparities in standards of care for early-stage breast cancer among ethnic groups, and about the contributions of socio-cultural factors on treatment decisions, and impacts on quality of life, this developmental/pilot study should contribute the information necessary to plan a larger study to understand these issues for specific ethnic groups.